It has long been known that static charges which develop between isolated bodies are discharged when those bodies are brought into sufficiently close proximity or contact. Potentials as high as 30,000 volts have been reportedly generated simply by a person walking on a synthetic carpet. In recent years this phenomenon, always regarded as something of a nuisance, has become a major concern to the manufacturers of sensitive electronic equipment. A static discharge of only a few hundred volts can severely damage or ruin expensive electronic circuitry, and such damage can occur at any stage of the assembly process or during transportation or storage.
Static charges can accumulate on production workers, on assembly work surfaces, and on any of the tools and containers used in the assembly area. The need to prevent static discharge requires that the entire assembly environment be constructed from materials which will quickly dissipate static charge, effectively interconnecting all workers, surfaces and equipment with a common electrical ground.
An ever increasing demand exists for static free environments in which electronic components can be manufactured. Conductive floor waxes or polishes are commercially available to maintain antistatic protection in manufacturing as well as research areas. Yet, in spite of the desirability for such antistatic compositions to provide resistivities of 10.sup.6 -10.sup.8 ohm/sq., these commercial materials can provide resistivities of only 10.sup.8 -10.sup.10 ohm/sq. while maintaining clarity and smoothness.
It is known from British Patent Application No. 2,148,915, to produce electronically-conductive, water-based wax or polish compositions containing neutralized carboxylic aminoester groups and quaternary ammonium compounds and having a resistivity of about 10.sup.9 ohm/sq. This reference discloses the use chemicals with anionic and cationic functionalities for electrical conductivity for a composition which provides high gloss and up to 60 days of antistatic protection. However, when high levels of quaternary ammonium compounds are used in these compositions to give resistivities below 10.sup.9 ohm/sq., the moisture sensitivity increases to a level where film toughness is jeopardized.
Antistatic polishes and waxes produced prior to the present invention exhibit several deficiencies in appearance and performance. Some give a hazy appearance or fail to give a smooth and durable surface in that the wax or polish is networked with microcracks. Not only do they have an undesirable appearance, but they crack and peel prematurely. Thus, a continuing need existed for an antistatic polish which provides lasting protection against antistatic discharging without haze or microcracking.
Within the last decade, extensive studies have been undertaken on metal salt/polymer complexes as electrical conductors. With the metal ion coordinated within a polymer matrix, the mechanism of conductance has sometimes been referred to as charge conductance. While the mechanism may be subject to controversy, several factors influencing the conductivity of these complexes are: (a) strong acid groups in the complex, (b) mobility of the complex, (c) solvent in which the complex is formed.
Alkali metal salt/polyethylene oxide complexes and their thermal and mechanical properties have been reported in references such as: C. Robitaille and J. Prud'Lomme, Macromolecules, 16, 665 (1983); J. M. Parker, P. V. Wright and C. C. Lee, Polymer, 22, 1305 (1981); and D. R. Payne and P. V. Wright, Polymer, 23, 690 (1982). While very good conductivity was reported for lithium salt complexes, Bekturov et al., Makromol. Chem., Rapid Commun., 6, 515 (1985), reported the stability of metal thiocyanate/PEO complexes as Na.sup.+ &gt;K.sup.+ &gt;NH.sub.4 +&gt;Li.sup.+. This suggests that the less stable Li.sup.+ /PEO complexes are providing the best conductivity. Thus, metal ions which complex too strongly may be too immobile to provide the best electrical conductivity. Yet, in spite of what was known about conductivity of metal salt/PEO complexes, it remained for the present invention to detail the composition and preparation of an improved antistatic floor polish.